These planets are in danger of asteroid strikes! Is Earth on the list?
Thousands of asteroids, meteors and comets have been whizzing past the Earth over millions of years. Throughout history, our planet has been a victim of multiple asteroid strikes, including the one that destroyed all dinosaur species. Concerns about a future asteroid strike like this has pushed scientists in developing anti-asteroid systems to protect the Earth. For years, we have believed that an asteroid strike is dependent on the gravitational pull of the planet and the coincidence of an asteroid moving close to the planet. However, now, a team of scientists are claiming that there are other factors that can determine whether a planet is an asteroid-magnet or not.
According to a report by Sky & Telescope, a team of researchers led by Darryl Seligman of University of Chicago have developed equations to determine whether a planet is more likely to accrete inbound comets and asteroids or not. These equations, reportedly, can determine whether a space rock moving closeby to the planet will be pulled in or pushed away by the planet. And it is dependent on three major parameters — the planet's mass and orbital distance and the eccentricity of the asteroid. For the unaware, the eccentricity of an asteroid is a measure of how circular or elongated its orbit is.
Some planets are more susceptible to asteroid strikes
After running their equations on a large set of planets and observing their historical data for asteroid strikes, the team believes that there is a strong correlation between the equation's prediction and behavior of space rocks around that planet. Seligman and his team found that planets which are classified as warm Jupiters, super-Earths, and sub-Neptunes are more likely to trap asteroids and comets as opposed to colder and more massive planets.
Warm Jupiters are gas giant exoplanets which are as big as Jupiter but have a very small orbital period between 10-200 days. Super-Earths, according to NASA, is a class of planets which are more massive than Earth yet lighter than ice giants like Neptune and Uranus. Finally, sub-Neptunes refer to planets which can have smaller radius than Neptune even though they may have a larger mass or a planet with a smaller mass than Neptune even though it may have a larger radius.
Incidentally, the planets that fall under these parameters are both bigger than the Earth and are often lighter than the Earth. As a result, this equation has not found that the Earth could be a hotspot for asteroids. Although this also does not prove that asteroids cannot strike the Earth either. History is proof of that. And all you have to do is look at the pock-marked face of the moon to know that the risk is ever-present.